package com.bjsdzk.common.utils;

import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.math.BigInteger;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

/**
 * 胜顶智控平台管理
 * MD5工具类
 *
 * @author YangTang
 * @time 2019/6/28.
 */
public class MD5Utils {

    private static final String KEY_MD5 = "MD5";

    private static final String privateKey = "!z@x#c$v%b-);";

    /**
     * MD5 不可逆加密
     *
     * @param data
     * @return
     */
    public static String encryptMD5Data(String data) {
        BigInteger bigInteger = null;
        try {
            data += privateKey;
            MessageDigest md = MessageDigest.getInstance(KEY_MD5);
            byte[] inputData = data.getBytes();
            md.update(inputData);
            bigInteger = new BigInteger(md.digest());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return bigInteger.toString(16).substring(3, 20);
    }

    /**
     * AES 可逆加密
     *
     * @param data
     * @return
     */
    public static String encryptAESData(String data) {
        byte[] encryptResult = encrypt(data, privateKey);
        String encryptResultStr = parseByte2HexStr(encryptResult);
        return encryptResultStr;
    }

    /**
     * AES 可逆解密
     *
     * @param data
     * @return
     */
    public static String decryptAESData(String data) {
        byte[] decryptFrom = parseHexStr2Byte(data);
        byte[] decryptResult = decrypt(decryptFrom, privateKey);
        return new String(decryptResult);
    }

    /**
     * 加密
     *
     * @param content  需要加密的内容
     * @param password 加密密码
     * @return
     */
    public static byte[] encrypt(String content, String password) {
        try {
//            KeyGenerator kgen = KeyGenerator.getInstance("AES");
//            kgen.init(128, new SecureRandom(password.getBytes()));
//            SecretKey secretKey = kgen.generateKey();

            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
            secureRandom.setSeed(password.getBytes());
            kgen.init(128, secureRandom);
            SecretKey secretKey = kgen.generateKey();

            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            byte[] byteContent = content.getBytes(StandardCharsets.UTF_8);
            cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(byteContent);
            return result; // 加密
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 解密
     *
     * @param content  待解密内容
     * @param password 解密密钥
     * @return
     */
    public static byte[] decrypt(byte[] content, String password) {
        try {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            kgen.init(128, new SecureRandom(password.getBytes()));
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance("AES");// 创建密码器
            cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
            byte[] result = cipher.doFinal(content);
            return result; // 加密
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 将二进制转换成16进制
     *
     * @param buf
     * @return
     */
    public static String parseByte2HexStr(byte[] buf) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < buf.length; i++) {
            String hex = Integer.toHexString(buf[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            sb.append(hex.toUpperCase());
        }
        return sb.toString();
    }

    /**
     * 将16进制转换为二进制
     *
     * @param hexStr
     * @return
     */
    public static byte[] parseHexStr2Byte(String hexStr) {
        if (hexStr.length() < 1)
            return null;
        byte[] result = new byte[hexStr.length() / 2];
        for (int i = 0; i < hexStr.length() / 2; i++) {
            int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
            int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
            result[i] = (byte) (high * 16 + low);
        }
        return result;
    }

//    public static void main(String[] args) {
//        String s = encryptAESData("8c176999c50ef04c4");
//        String aaa = decryptAESData("FD287BDDBD1FD7D163658553D41FE5C83CFC3E4A34D5A223823C79D1A3FFEA6C");
//        System.out.println(s);
//        System.out.println(aaa);
//    }
}
